1. Field
The present disclosure relates generally to titanium alloy and, in particular, to processing titanium alloy to have desired mechanical properties. Still more particularly, the present disclosure relates to a method and apparatus for forming fasteners from titanium alloy with desired mechanical properties.
2. Background
Titanium alloys are metals that comprise a mixture of titanium with other chemical elements. Titanium alloys have a high strength-to weight ratio, are corrosion resistant, and exhibit higher tensile strength and toughness than other materials, even at increasing temperatures. For these reasons, titanium alloys are often used in aerospace and aeronautical applications. For example, without limitation, titanium alloy is used to form landing gear components, engine components, mechanical fasteners, and other suitable structures.
Typically, titanium parts for aerospace applications are formed from Ti-6Al-4V alloy, which is an alpha-beta titanium alloy comprised of about six percent weight aluminum, about four percent weight vanadium, other elements in small quantities, and the balance is titanium. Aerospace industry standards mandate that parts formed from titanium alloy, such as Ti-6Al-4V, have certain material properties. For instance, the standards mandate that aerospace fasteners must have a certain amount of shear strength and tensile strength to be used in aircraft.
To achieve these material properties, certifying bodies establish chemical composition and processing guidelines for fasteners made of titanium alloy. For example, current aerospace guidelines require Ti-6Al-4V to be formed with a maximum amount of oxygen, iron, carbon, and nitrogen. Further, the standards advocate using a solution treating and age process to improve the shear strength and tensile strength of a fastener made from the titanium alloy.
During a solution treating and age process, material is placed in a furnace for the solution treatment, quenched, cleaned, and then aged to strengthen the material. This process may take several hours and require bulky machinery that takes up valuable manufacturing space. The heat treat process creates surface contamination, which makes the surface brittle and needs to be removed. Consequently, this process takes more time and uses more resources than desired.
In addition, as the thickness of the solution treated and aged material increases, the ability of the material to maintain a desired shear strength and tensile strength decreases. As a result, solution treated and aged fasteners with a larger diameter may not perform as well as desired.
Therefore, it would be desirable to have a method and apparatus that take into account at least some of the issues discussed above, as well as other possible issues. Specifically, it would be desirable to provide a lightweight titanium alloy material for aerospace fasteners that meets industry requirements, while saving time and cost of manufacture.